1. Field of the Invention
The present invention relates to vascular occlusion devices employed for occluding vascular structures. More particularly the disclosed device and method relate to an occlusion device which is configured for implantation through the extremely narrow and serpentine vascular structures of newborns and infants where heretofore such devices were not employable. Further, the device provides a novel deployed implant especially configured to maintain a secure mount at the implant site which in infants and newborns is especially challenging due to the small nature of such sites and the thin and delicate surrounding tissue.
2. Prior Art
There are many instances in medicine where patients may have blood vessels and other unwanted vascular structures (sometimes man made structures) which need to be blocked or segregated from fluid passages of the vascular system, in order to treat the patient. Such devices may include stents or in a majority of cases where an occlusion of the site is desired, shaped metal coils are employed which, once released, provide a means for blocking an intended vascular passage.
Such metal coil implants are initially engaged in a catheter or delivery tube in a linear fashion and an elongated shape or configuration, in order for the shaped metal implant to follow the axial conduit within the catheter for implantation from the distal end of the catheter at the delivery site. Formed of coiled memory metal, the coils of the implant, upon deployment from the distal end of the catheter, wind to their original shape to form a blocking component configured to block or segregate a section of the vascular system desired from the adjacent system.
However, because such coil devices are delivered to a deployment site within these vascular structures with catheters, when the patient is an infant or newborn child, a severe problem arises. This is because when these vascular structures exist in very small children and infants, as well as in difficult to access parts of the body (as is the case for the brain, coronary arteries or other tortuous vessels in the abdomen), it becomes necessary that the coil-shaped implant be delivered by translation through the conduit of very small tubes called microcatheters.
However, because the physical requirements of the cross section of the axial conduit of such small microcatheters, conventionally sized and tensioned coil-shaped occlusion devices do not work well. Most implants have cross sections of the coil of the implant, which even in an elongated positioning of the wire forming the coil, exceed the diameter of microcatheter devices. Those that have a sufficiently narrow coil diameter to translate through the conduit of a microcatheter when deployed have not worked well in infants and children because they lack the tension on deployment for a secure engagement to the vascular or surrounding tissue. Such conventional devices of lower tension, in addition, have shapes which on deployment lack the ability to achieve a secure compressive engagement to occlude apertures in infants, such as between heart chambers, and remain engaged to the tissue surrounding the aperture being sealed.
Employment of such conventional coils can result in a dismounted coil for instance when deployed to seal a patent ductus arteriosus (PDA) in an infant or newborn who have high heart rates of 150 beats or more. In addition to the movement imparted by the heart beats, such infants have thin delicate tissue which must provide the engagement for the deployed implant. Such a dismount should it occur, is life threatening and requires immediate more invasive surgery to remove the dismounted implant which is additionally life threatening.
As such, there is a continuing unmet need for catheter-delivered implant capable of translation and delivery through a microcatheter which is required in the treatment of infants and newborns and in very small vascular system areas in adults. Additionally, such a device, on deployment, must achieve the desired occlusion and concurrently a secure engagement to the tissue of the patient, in high blood flow areas which impart extra force against the implant which can lead to dislodgement.
The present invention solves the shortcomings of the current art, in providing a vascular occlusion coil-type implant which can be delivered via translation through a microcatheter for implantation in infants and newborns and small blood vessels. The disclosed device in such a communication through the axial passage of a microcatheter, once deployed and engaged with patient tissue, provides the desired occlusion for very high flow vascular structures. The disclosed device accomplishes these tasks, using a coil which is coiled to extremely high tension resistance to coil-elongation to a substantially straight configuration elongated for translation through a microcatheter by hand pushing on the control wire, or using a pushing component engaged to the proximal end of the catheter to push on the control wire.
Further, once released, the coil device herein assumes an overlapping conical shape at one end which forms a particularly secure mount when a second end of the coil reverses on deployment to cover the narrow end of the first deployed end. As noted, once deployed from a microcatheter, the unique shape and overlapping configuration of the deployed coiled implant, provides the requisite strength to block an area of high blood flow and resulting high pressure forces. Further, the unique overlapping coiled configuration achieves the necessary engaging compressive force against surrounding tissues to maintain a permanent mount in the patient and thus avoid a life-threatening dismount.
The forgoing examples of related art and limitation related therewith are intended to be illustrative and not exclusive, and they do not imply any limitations on the invention described and claimed herein. Various limitations of the related art will become apparent to those skilled in the art upon a reading and understanding of the specification below and the accompanying drawings.